Chris Pratt and his girlfriend Katherine Schwarzenegger double dated with her famous father over the weekend.

Chris Pratt

Chris Pratt

The 'Guardians of the Galaxy' star was seen enjoying breakfast with his other half as well as Arnold Schwarzenegger and his girlfriend Heather Milligan in Los Angeles on Sunday.

The foursome dined at the Fairmont Miramar Hotel & Bungalows in Santa Monica, before Chris headed to church with Katherine.

A source told E! News: "Everything seems to click with them and works. They have the same values, lifestyle and priorities. She has always been good with children, but she really shines and has stepped in to this role perfectly. She knows her place with him and is there to have fun and support him. From the moment they met, it just seemed different for Katherine. This is definitely the most serious relationship she has had. They haven't been together that long but everyone is rooting for an engagement to happen soon."

Meanwhile, Chris and Katherine are said to be "inseparable".

An insider shared: "The moment Chris and Katherine started dating, everything fell into place and they seemed inseparable. They just love each other's company and have so much in common. They spend a great deal of time together. Chris and Katherine have the full support of her family and Maria [Shriver] feels they are a match made in heaven."

And it was previously claimed that the 'Guardians of the Galaxy' star and the author are such a "good fit", that their friends wouldn't be surprised if they got engaged in the near future.

An insider said: "They're such a great fit together. It's only been a few months but Chris and Katherine are both very serious about the relationship and their friends wouldn't be surprised if they got engaged sooner rather than later. Katherine has spent time with Chris' family and they all love her too. She fits in really well with them and vice versa."